Contents
Introduction
An important part of routine diabetes care is to check the feet for signs of diabetic foot disease – mainly peripheral neuropathy (and associated skin integrity), but also the increased risk of peripheral vascular disease. Diabetes affects blood vessels, causing a loss of blood supply that can lead to ischemia and tissues damage. This is particularly the case in the peripheries. The feet are the most distal tissues from the heart and so the most likely to be affected first by the pathological changes in diabetes.
Introduce yourself
Get good and proper consent. Say exactly what you are going to do.
Inspect
Look at the feet
- Are there any ulcers?
- Skin damage? Look for calluses, cracked skin, nail changes (e.g. ingrowing nail), skin discolouration
- How is the general foot hygiene (does this look like a patient who takes care of their feet)? Does the patient look comfortable?
- Ask them if they are experiencing any difficulty with their feet. sensory nerve loss is the first change seen in diabetic neuropathy – so often patients can have damage to their feet without realising it. if they are experiencing pain / discomfort or tingling sensations, it is likely the irreversible changes are quite far advanced.
Palpate
- Feel for the posterior tibial and the dorsalis pedis arteries. Posterior tibial is on the inner aspect of the ankle, the dorsalis pedis is on top of the foot lateral to the tendon of the big toe. The dorsalis pedis can be particularly difficult to palpate. If you press too hard you will occlude it. If you are finding it hard to feel, you can start by pressing hard and gradually let off to see if you can feel it. You may also want to ask the patient to extend their big toe to exaggerate the tendon, making the landmark more prominent and thus making it easier to palpate in the right place.
- Feel how warm the feet are- checking peripheral perfusion. Note that on a cold day, this is not a particularly reliable sign!
- Press on the nail beds to test capillary return –press for 5 seconds, then release and watch as the nail returns from pale to pink/red. This time should be less than 3 seconds, but could also be longer if it is cold. Compare both feet.
Check nerve function
- Tell the patient it won’t hurt and show this on yourself. Using the soft touch first. Often care centres have a ‘pen’ tool specially designed for the diabetic foot check, with a soft touch microfilament at one end, and a pain receptor tester at the other. Do not drag the microfilament across the surface of the skin, just gently press it against the skin and aski the patient for a response. The purpose of the microfilament is to visibly show when you are applying to much pressure. The filament will bend if you press too hard.
- Demonstrate the soft touch on the back of the patient’s hand so they know what sensation to expect. Then test the feet. Start distally (sensation is lost here first) and move up the foot and then up the leg. Sensation is lost in a glove and stocking pattern consistent with all peripheral neuropathies.
- If light touch sensation is lost, then use the sharp (pain) receptor tester. Again, mark out the pattern of sensory loss.
- Use the tuning fork. A 128Hz tuning fork should be used for this (proprioception). Again demonstrate it on yourself, then try it on the hand or perhaps clavicle of the patient so they know what it feels like. Again, start distally, and use bony prominences (usually the MTP joint (“knuckle”) of the big toe. vibration testing is more sensitive than touch.
Interpreting Results
Grade 0 – no abnormalities on examination
- Action – advise patient to check their own feet regularly for any changes, and to make an appointment if they notice any ulcer, callouses, skin or nail changes, or any altered sensation. Review in 12 months, manage in primary care
Grade 1 – No ulcer, but one of the following: callus, ingrowing toe nail, absent pulse, loss of sensation
- Action – give foot care advice. Refer to podiatry if any deformity / nail changes. Assess glycaemia control. Review in 6 months, manage in primary care, unless claudication @ <200m walking distance.
Grade 2 – Grade 1 PLUS previous Hx of ulcer, skin changes, minor ongoing ulcer
- Action – refer to podiatry and to diabetologist/ specialist diabetic foot care. Consider refer to vascular care if claudication @ <200m walking distance. Cosndier use of shoe inner-soles / specialist shoes, encourage tighter glycaemic control. Review at 3 months
Grade 3 – ACTIVE ONGOING PROBLEM – including acute ischaemia / necrosis / gangrene, cellulitis / infection, large ulcer, foot pain
- Action – REFER IMMEDIATELY – to diabetologist / specialist diabetic foot care, plus referral to vascular care due to ischaemia. PLUS all of grade 2 actions.